Cell Theory: All living things are made up of cells, and cells arise from pre-existing cells.
Chromosome Theory of Inheritance: Genes are located on chromosomes, and inheritance patterns are determined by the behavior of chromosomes during meiosis.
Theory of Evolution: Characteristics of species can modify from generation to generation, and species are related by common ancestry.
DNA and Chromosomes
Chromosome Composition: Chromosomes consist of DNA, the hereditary material.
Genes: Specific segments of DNA that code for proteins or cell products.
In eukaryotic cells: DNA is in the membrane-bound nucleus.
In prokaryotic cells: DNA is in a region called the nucleoid.
Importance of Genes: Genes determine physical appearance and physiology.
Central Dogma of Biology
Flow of Information: DNA -> RNA -> Protein.
DNA Structure: Double-stranded helix, discovered by James Watson and Francis Crick in 1953.
DNA Bases:
Adenine (A)
Thymine (T)
Cytosine (C)
Guanine (G)
Base Pairing: A pairs with T, and C pairs with G.
Genetic Code and Diversity
All organisms use the same four DNA bases, enabling genetic code translation into proteins.
Proteins: Critical for cell tasks, forming structural components, and promoting chemical reactions.
Diversity of Life: Differences in DNA sequences lead to variations in species (e.g., finch beak size, giraffe neck length).
Understanding Genetics
Genome: The entire library of genetic instructions inherited by an organism.
Human Genome Project: Completed in 2001, sequenced the human genome in 15 years at $3 billion cost.
Current Technology: Sequencing a human genome costs as low as $1,000 today.
Study Recommendations
Read textbook chapters before lectures to clarify confusion.
Engage in critical thinking and summarize relationships between DNA, genes, and proteins.
Prepare questions for class discussions based on lecture and reading.
Final Thoughts
The lecture emphasized understanding the relationship between genetic information and diversity.
The human genome sequencing opens discussions about privacy and access to genetic information.